Subjective probabilities are derived mathematically from reliable historical data.

Subjective probabilities are based on personal beliefs, opinions, and judgments, rather than objective or historical data. They are often used in situations where historical data is not available or not applicable, such as in forecasting, risk assessment, or decision-making under uncertainty. However, subjective probabilities can still be informed by relevant information and expertise, and can be calibrated and updated based on feedback and experience.